Weak dipole Moment of τ in e⁺e⁻ collisions with longitudinally polarized electrons

Abstract

It is pointed out that certain CP-odd momentum correlations in the production and subsequent decay of tau pairs in e⁺e⁻ collisions get enhanced when the e⁻ is longitudinally polarized. Analytic expressions for these correlations are obtained for the single-pion decay mode of τ when τ⁺τ⁻ have a "weak" dipole form factor (WDFF) coupling to Z. For e⁺e⁻ collisions at the Z peak, a sensitivity of about (1−5)×10⁻¹⁷ e cm for the τ WDFF can be reached using a single τ⁺τ⁻ decay channel, with 10⁶ Z's likely to be available at the Stanford Linear Collider with e⁻ polarization of 62%-75%.